20005 research outputs found
Sort by
Proteins and peptides
No full textMarine-derived proteins and peptides represent a unique resource with exceptional nutritional, functional, and bioactive properties. This chapter explores the diverse sources of marine proteins, including fish, molluscs, crustaceans, algae, and microorganisms, and highlights their structural and compositional characteristics. The bioactive potential of marine peptides, including antioxidant, antimicrobial, antihypertensive, anti-inflammatory, and anticancer properties, is discussed alongside their industrial applications in food, nutraceuticals, pharmaceuticals, and biomaterials. Furthermore, this chapter reviews common and novel extraction and purification techniques that enhance the recovery and functionality of marine-derived proteins and peptides. Future directions for research and development should focus on optimising bioavailability, enhancing bioactivity, and expanding industrial applications. By leveraging innovative technologies and sustainable practices, marine-derived proteins and peptides have great potential for addressing global challenges in nutrition, health, and sustainability
Recycled concrete aggregate in self-consolidating concrete: a systematic review and meta-analysis of mechanical properties, RCA pre-treatment and durability behaviour
No full textThis systematic review and meta-analysis per PRISMA 2020 addresses the use of recycled concrete aggregates as a replacement for aggregates in self-consolidating concrete for structural and non-structural use. It provides a comprehensive evaluation of the available research and offers a synthesised overview of the potential use of recycled concrete aggregate in self-consolidating concrete beyond standardised replacement levels. A total of 256 research papers were obtained from different databases, and after a detailed content review, only 24 unique experimental research studies fulfilled the review criteria. Data were extracted on recycled concrete aggregate source, pre-treatment, replacement ratio, mix proportions, fresh properties, strength, stiffness, and durability. It was observed across all studies that the recycled concrete aggregates originated from precast concrete rejected elements with a low water-to-cement ratio, producing an equal or stronger concrete than the reference concrete in the studies; however, none of the studies included in this research resulted in a higher modulus of elasticity than the corresponding reference concrete. Additionally, moderate aggregate replacement (20–50%) preserved the workability, whereas high replacements (75–100%) affected fresh concrete properties as well as increased shrinkage and creep. The inclusion of fine recycled concrete aggregate in addition to coarse recycled concrete aggregate has a larger effect on lowering compressive strength and stiffness in the concrete. Overall, high-quality coarse recycled concrete aggregate (precast rejects or screened demolition waste)—an aggregate replacement level of around 50%—facilitates the production of sustainable self-consolidating concrete, whereas full replacement requires aggregate pre-treatment and a carefully optimised mix design
Research on fire detection algorithm of equipment compartment under EMU based on multi-parameter fusion
No full textThe smoke detection technology has high false alarm rate and is greatly affected by ambient wind speed. It is difficult for the temperature detector to realize early alarm, and there are risks of missing alarm and delayed alarm. Composite fire detection technology is an effective means to solve the above problems. In the application of composite fire detection algorithm, there are some problems such as false positives in frame-by-frame state judgment, delay alarm and fuzzy alarm time caused by unclear setting of detection interval length. In this paper, 7 standard combustibles in the equipment compartment under vehicle were tested on the fire detection simulation test platform, and typical fire characteristic parameters such as ambient temperature, CO concentration, VOC concentration and smoke concentration were obtained under 3~6 m/s horizontal wind field. Through ensemble learning and LSTM algorithm, the following conclusions are obtained: The detection interval length with the highest accuracy of state recognition is 30~40 s; The state determination algorithm model based on Xgboost - LSTM algorithm is constructed. Increased to 92.56%, the model can efficiently learn sample experimental data and accurately judge the environmental state; Within the detection interval length, the accurate alarm rate of smoulder is 78%, the accurate alarm rate of open flame is 96%, the false alarm rate and false alarm rate are 4% and 2%. The wavelet transform algorithm can judge the fire state within the detection interval length and achieve accurate alarm
Finite element simulations of ice impacts on a ship hull using the MCNS model
No full textIn this study, ice floe impacts on a non-ice-strengthened ship structure are investigated using the finite element method (FEM) with the Mohr-Coulomb nodal split (MCNS) as an ice material model. With this analysis, we address three questions: How does the shape of the ice affect the impact? Is the location where the impact occurs significant? How does the direction of impact influence the loads experienced by the ship? The ice shapes used for this study are modeled based on previous experimental analyses and include round, flat-parallel, and sharp geometries. Impact locations considered are the plate field, bulkhead, and longitudinal stiffener, with impact directions of 0 deg (glancing impact), 30 deg, 60 deg, and 90 deg (perpendicular impact). The study compares load magnitude, plastic deformation, and strain energies across these scenarios to pinpoint significant influencing factors. Findings are compared against existing experimental and literature data, highlighting the critical impact parameters and identifying the worst-case scenario. The study indicates that all three parameters significantly affect the impact. Round and flat-parallel ice shapes result in higher loads compared to the sharp shape. The greatest deformations occur in the plate field and in the bulkhead impact locations. Additionally, the loads increase as the impact becomes more perpendicular
Nachhaltigkeit in der Produktentwicklung
No full textSustainability is important in society and the economy, but complicated to implement in products. The Scientific Society for Product Development (WiGeP), a network of leading professors and industry representatives active in German-speaking countries, sees sustainability as an integral part of its field. The Scientific Society’s position paper therefore shows how methods and processes can be further developed in future research in order to increase the integration of sustainability aspects into methodical product development
Riemannian approach to the Lindbladian dynamics of a locally purified tensor network
No full textTensor networks offer a valuable framework for implementing Lindbladian dynamics in many-body open quantum systems with nearest-neighbor couplings. In particular, a tensor network Ansatz known as the locally purified density operator employs the local purification of the density matrix to guarantee the positivity of the state at all times.Within this framework, the dissipative evolution utilizes the Trotter-Suzuki splitting, yielding a second-order approximation error. However, due to the Lindbladian dynamics’ nature, employing higher-order schemes results in nonphysical quantum channels. In this work, we leverage the gauge freedom inherent in the Kraus representation of quantum channels to improve the splitting error. To this end, we formulate an optimization problem on the Riemannian manifold of isometries and find a solution via the second-order trust-region algorithm. We validate our approach using two nearest-neighbor noise models and achieve an improvement of orders of magnitude compared to other positivity-preserving schemes. In addition, we demonstrate the usefulness of our method as a compression scheme, helping to control the exponential growth of computational resources, which thus far has limited the use of the locally purified Ansatz
Significant improvement of the fatigue performance of ER70S-6 WAAM un-milled structures: a Cu/Ni multilayer nanotechnology approach
No full textIn recent years, the adoption of Wire Arc Additive Manufacturing (WAAM), now defined as Directed Energy Deposition based on Gas Metal Arc Welding (DED-Arc), in steel construction has increased significantly. However, the sequential layer deposition inevitably creates surface notches that cause high stress concentrations, leading to fatigue crack initiation. The current industrial standard for post-processing, CNC milling, is time-consuming and resource-intensive. A novel research approach focuses on directly controlling critical residual stresses of as-built specimens by introducing near-surface compressive residual stresses using a Cu/Ni nanostructured metallic multilayer (NMM). This study investigates the effect of NMM on DED-Arc structures and extends its application to metallic 3D-printed components. Optical microscopy provides detailed surface morphology and reliable roughness measurements, while X-ray diffraction (XRD) confirms the presence of residual tensile stresses in the NMM and the resulting residual compressive stresses in the steel substrate. Preliminary tension-tension fatigue testing provides insights into the fatigue strength increase due to NMM treatment of DED-Arc dogbone specimen
Die HOOU an der TUHH : Erfahrungen und Erfolge 2024
No full textIm Jahr 2024 wurden 13 Projekte im Rahmen der Hamburg Open Online University (HOOU) an der TUHH umgesetzt. Die projektspezifischen Erfahrungen und Erfolge werden in dieser Broschüre zusammenfassend dargestellt
Influence of spatial engagement conditions on workpiece temperature in grinding of unidirectional CFRP
No full textCarbon Fibre Reinforced Polymers (CFRP) are favoured for their high strength to weight ratio, excellent directional mechanical and thermal properties, and the ability to be optimized in the direction of stress or heat flow. These properties make it ideal for power transmission applications. Heating of the machined surface during grinding can lead to reduced workpiece quality, particularly if the glass transition temperature of the matrix is exceeded. The selection of tool-material, process parameters and cooling strategy significantly influences heat flow from the region of tool-workpiece interaction and changes in the workpiece temperature. Machining unidirectional CFRP is challenging due to its anisotropic behaviour, resulting in different machining temperatures for identical parameters with different fibre orientations.
A universal process-independent model describing the spatial engagement conditions during oblique cutting of unidirectional CFRP was used. The model introduces the spatial fibre cutting angle θ0 and the spatial engagement angle φ0. Using this description, an experimental setup for investigating the workpiece surface temperature of CFRP for all possible engagement conditions was developed.
In this paper, the machining temperature is determined for all possible spatial engagement conditions during the machining of CFRP using thermographic camera. Furthermore, the influence of the cutting material in the cases of corundum and diamond is analysed as well as the influence of the cutting speed